New reports of somatic chromosome number and symmetric or asymmetric karyotype estimation of Sechium edule (Jacq.) Sw. (Cucurbitaceae)


  • Sanjay Kumar Department of Botany, Banaras Hindu University, Varanasi, UP 221005
  • Asikho Kiso Department of Botany, Nagaland University, Lumami, Nagaland798627



Sechium edule (Jacq.) Sw., mitosis, somatic chromosome number, karyotype, inter and intra chromosomal symmetry/asymmetry estimation


Sechium edule (Jacq.) Sw. distributed well in Eastern Himalayan region, fourteen genotypes collected randomly from Kigwema village, Kohima (Nagaland) at an average altitude of 1538 masl (meter above sea level) with 25.61°N latitude and 94.35°E longitudes. Somatic chromosome numbers are diploid in nature. Chromosome numbers are in agreement and comparable with earlier reports except 2n=2x=22. The chromosome number 2n=2x=22 could not be traced out in the present material collected for study. Two (2) new chromosome numbers 2n=2x=32 and 2n=4x=52 were recorded and expected to be diploid and tetraploid in nature respectively. It was expected that tetraploid (2n=4x=52) number of chromosome might be originated from the earlier reports of diploid chromosome number 2n=2x=26. Both chromosome numbers 2n=2x=32 and 2n=4x=52 are reported for the first time by the authors in the present study. Range of chromosome length was recorded in between 0.501 – 1.343. The range of chromosome length are in agreement with earlier reports of 0.700 – 0.900 approximately. Range of chromosome length suggested minute (<1µm) and small (1-3µm) size of chromosomes with small differences and variations in chromosome length (CVCL). Inter-chromosomal indices (A2 and Rec), intra-chromosomal index (particularly, Stebbin’s classification) and both inter and intra chromosomal indices (DI and GI) estimated symmetric nature of the karyotype.


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Adanson M. 1763. Familes des Plantes, Volume I and II, Vincent Paris.

Bisognin D A. 2002. Origin and evolution of cultivated cucurbits. Cinecia, Santa Maria 32(5): 715-723.

Browne P. 1756. Civil and Natural History of Jamaica. London, England.

Cogniaux A. 1881. Cucurbitacées. Monographiae Phanerogamarum. (De Candolle A. and De Candolle C., Eds.), Masson G., Paris 325-951.

De Donato M, Cequea H. 1994. A Cytogenetic Study of Six Cultivars of the Chayote, Sechium edule Sw. (Cucurbitaceae). Journal of Heredity 85: 238-241.

Goldblatt P. 1990. Index to plant chromosome numbers (1988-1989). Monogr. Syst. Bot. Missouri Bot. Gard., Missouri. 90pp.

Jacquin NJ. 1788. Selectarum Stirpium Americanarum Historia. Leiden.

Jacquin, N.J. 1763. Selectarum Stirpium Americanarum Historia. Wenen, Austria.

Jain J R, Satyan K B, Manohar S H. 2015. Standardization of DNA isolation and RAPD-PCR protocol from Sechium edule. Int. J. advanced Life Sci. 8(3): 359-363.

Kapoor C, Kumar A, Pattanayak , Gopi R, Kalita H, Avasthe R K, Bihani S. 2014. Genetic diversity in local Chow-chow (Sechium edule Sw.) germplasm of Sikkim. Indian J Hill Farming 27 (1): 228-237.

Lira R, Nee M. 1999. Two new combinations in Sechium (Cucurbitaceae) from Central America and a new species from Oxaca, Mexico. Novon 2: 227-231.

Lira R, Nee M 1999. A new species of Sechium sect. Frantzia (Cucurbitaceae, Sicyeae, Sicyinae) from Mexico. Brittonia 51(2): 204-209.

Mercado P, Lira R, Castrejón J.1993. Estudios Cromosómicos en Sechium P. Br. Y Sicana Naudin (Cucurbitaceae).Pp. 176 in Resúmenes XII Congreso Mexicano de Botánica. Mérida, Yucatán: Sociedad Botánica de México.

Mercado P, Lira R. 1994. Contribución al conocimiento de los numerous cromosómicos de los géneros Sicana Naudin y Sechium P. Br. (Cucurbitaceae). Acta Bot. Mexicana 27: 7-13.

Newstrom L E. 1991. Evidence for the origin of chayote, Sechium edule (Cucurbitacae). Economic Botany 45(3): 410-428.

Sanwal S K, Yadav R K, Singh P K, Rai N 2008. Variability and genetic diversity studies in indegenus chow-chow genotypes of northeast India. Indian J Hort. 65(2): 167-170.

Singh AK. 1990. Cytogenetics and Evolution in the Cucurbitaceae. Biology and Utilization of the Cucurbitaceae (Bates D M., Robinson R W, Jeffrey C., Eds.) Cornell University Press, Ithaca, NY 10-28 pp.

Swartz O. 1800. Flora Indiae occidentalis aucta atque illustrate sive descriptions plantarum in prodromo recensitarum. Tomus II. 643 – 1230.

Thakur AK. 2016. Sicyos angulatus L. (Cucurbitaceae): a new adventives species for the flora of India. Current Science 111 (5): 789.




How to Cite

Kumar, S., & Kiso, A. (2022). New reports of somatic chromosome number and symmetric or asymmetric karyotype estimation of Sechium edule (Jacq.) Sw. (Cucurbitaceae). Caryologia, 75(1), 89-97.